In the art of refinishing furniture and other previously painted or varnished objects, a large part of the effort is devoted to the removal of the old paint or varnish. To make this job easier, chemicals are utilized to loosen the finish so that it can be scraped or washed from the surface. The use of chemicals, however, has introduced some new problems. The most widely used stripping chemical is methylene chloride which has been found to be a health hazard and can only be safely handled in closed stripping booths.
The nozzles presently employed in such stripping booths utilize small orifices to form a fine, mist-like spray; and these small orifices have a tendency to clog whenever particulates are present in the stripping chemical. As a consequence, either an apparatus with once-through chemical utilization or one having a fine filter is required. Unfortunately, an intricate filtering system is necessary to protect the high pressure pumps which must be employed to push a liquid even at low flow rates through small orificed nozzles. Moveover, a volatile chemical like methylene chloride must be processed with a layer of a wax-like substance that floats on the surface of the chemical to minimize evaporation losses. But when liquid under high pressure is forced through small orificed nozzles, a cooling effect occurs; and the wax-like layer thickens, contributing further to the problem of nozzle plugging. With nozzle plugging, not only is production slowed down but the operator must enter the stripping booth to service the nozzles and, in the process, contact the chemical which, when dispersed as a fine mist, takes a long time to settle out of the air.
Small orificed nozzles further compound the problems associated with minimizing operator exposure to the stripping chemical because high evaporation losses accompany the production of a fine mist, especially one which must be generated for an extended period of time to coat the surfaces of a work piece due to the low flow rates in the prior art. Moreover, running the large horsepower pumps needed to obtain enough flow at the required pressure through such nozzles is costly.